Contrasting impacts of acclimation and adaptation of photosynthetic capacity to temperature and CO2 across biomes

Oliver, Rebecca J. ORCID: https://orcid.org/0000-0002-5897-4815; Mercado, Lina M. ORCID: https://orcid.org/0000-0003-4069-0838; Medlyn, Belinda E. ORCID: https://orcid.org/0000-0001-5728-9827; Harris, Phil P. ORCID: https://orcid.org/0000-0002-4834-7746; Clark, Douglas B. ORCID: https://orcid.org/0000-0003-1348-7922. 2025 Contrasting impacts of acclimation and adaptation of photosynthetic capacity to temperature and CO2 across biomes. Global Biogeochemical Cycles, 39 (7), e2024GB008398. 20, pp. 10.1029/2024GB008398

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Official URL: https://doi.org/10.1029/2024GB008398

Abstract/Summary

The response of photosynthesis to temperature and CO2 is poorly represented in land surface models, contributing uncertainty to estimates of the land carbon sink. We assess the sensitivity of carbon uptake to temperature adaptation and acclimation of photosynthetic capacity and CO2 acclimation of photosynthesis in the JULES model forced with an RCP8.5 climate scenario. Simulations show enhanced global gross primary productivity (GPP) when these processes are included, but over time the enhancement of GPP is weakened. In extratropical regions, temperature acclimation enhances GPP by aligning the photosynthetic temperature optimum with seasonal temperatures, allowing higher rates of carbon assimilation. In the tropics, temperature adaptation weakens the rate of global carbon uptake by reducing the CO2 sensitivity of photosynthesis and limiting the CO2 fertilization response, while acclimation sustains higher rates of photosynthesis as temperatures rise. Combined, our results suggest enhanced thermal resilience of modeled global GPP to warming. Downregulation of photosynthetic capacity in response to elevated CO2 could substantially affect future GPP. However, this response remains uncertain, highlighting the need for improved understanding and representation of CO2 acclimation across biomes, especially in tropical ecosystems where field data are scarce. Results suggest models omitting these processes may underestimate global carbon uptake and ignore important spatial variability in response to climate change.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1029/2024GB008398
UKCEH and CEH Sections/Science Areas:	Water and Climate Science (2025-) Unaffiliated
ISSN:	0886-6236
Additional Information:	Open Access paper - full text available via Official URL link.
Additional Keywords:	acclimation, adaptation, land surface model, gross primary productivity, JULES photosynthesis
NORA Subject Terms:	Earth Sciences Ecology and Environment Atmospheric Sciences
Related URLs:	Code Code Code
Date made live:	08 Jul 2025 09:58 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/539800

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1029/2024GB008398

UKCEH and CEH Sections/Science Areas:

Water and Climate Science (2025-)
Unaffiliated

ISSN:

0886-6236

Additional Information:

Open Access paper - full text available via Official URL link.

Additional Keywords:

acclimation, adaptation, land surface model, gross primary productivity, JULES photosynthesis